I agree with you--this is a "weird question." It assumes that all "white marriages" are only between two white people and all "black marriages" are only between two black people, which is a flawed assumption. In addition, the answer should not have to be based on anyone's opinion but on statistical data. That being said, here is some data which might help you as you decide how to answer this question.

The current CDC marriage statistics show that 51% of white women are married, but only 44% of white men are married. That, of course, means that 7% of white women are currently married to someone of a different race, which muddies the statistical water.

The Washington Post reports:

Among black women, half of first marriages end in divorce, a rate that is far greater those for white, Hispanic and Asian women.... Most had divorced within eight years of their wedding.

Nearly a third of adults never marry at all.

As with divorce, marriage rates vary with race and ethnicity. Seven out of 10 black women in their 20s have never married.

According to the Marriage project, people without a college degree are three times more likely to get divorced within ten years than those with a college degree.

The CDC statistics report that only 11% of marriages are between people who have college degrees, though it is unclear whether that means both people in the marriage have degrees. All the other marriages are between people who have no college degrees (28% have no high school diploma). Again, though, it is unclear if this applies to both halves of the couple (I linked the site below so you can check the data for yourself.)

Money is also a factor in how long-lasting marriages are, with the most affluent generally staying married longer than those who are not. Added to that is the concept of strong marriage role models, which also play a part in how successful a marriage is.

The Washington Post downplays the divorce rate:

Most Americans marry once and stick to it.

According to the census statistics, more than half of the nation’s married couples have been together at least 15 years. About a third have marked their 25th anniversaries, and 6 percent have been married more than 50 years.

To say that marriage and race is complicated is an understatement, since each issue is complicated on its own. While there is probably statistical data which could accurately answer your question, I could not find it.

To review, marriage is more likely to last if both people have a college degree, some financial stability, and good marriage role models in their lives. This is presumably true for all races and ethnicities, so it stands to reason that those who do not have these statistical advantages are more likely to have failed marriages. It may be that black marriages are more likely to end in divorce, because of these factors, than white couples. However, one more consideration (as if things are not complicated enough) is that the statistics are skewed because almost twice as many whites as blacks get married (CDC stats, again). And, by the way, which race lives longer (and can therefore stay married longer)?

This question presumes there is something fundamentally, or at least culturally, different between blacks and whites and that blacks are somehow not as committed to the contract and covenant of marriage as whites. That may or may not be true; you will have to decide how you feel about the data.

P.S. Just ran across an article which mmight also give you a little perspective on why the number of blacks who get married is so much less than whites. Just another aspect of the issue to consider as you formulate your answer. Best of luck!